Induction furnace



c. s. WILLIAMS INDUCTION FURNACE Filed Aug. 14, 1929 FZ'gJ.

HNVENTOR 67/)70/2 5 M'll/bms.

' ATTORNEY Patented June 16, 1931 CLIFTON S. WILLIAMS, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING- noose nrzcrnrc & vnnm MANUFACTURING COMPANY, A CORPORATION 01' PENNSYL- nmuc'rrorf FURNACE Application filed August 14, 1929. Serial No. 385 ,791.

My invention relates to electric furnaces and more particularly to electric furnaces of the induction type. An object of my invention is to provide a relativelysimple, inexpensive and highly efficient heating structure for an induction furnace.

Another object of my invention is to provide a novel coil structure for an induction furnace of the surrounded-pool type.

In practicing "my invention, I provide a crucible forcontaining metal or material to be melted, which is surrounded by a pair of energizing coils, the axesof which are symmetrically, oppositely, and angularly inclined relative to the longitudinal axis of the crucible, in such manner as to leave uncovered the top part'of the crucible.

In the single sheet of drawings,- Figure 1 is a view in vertical section; taken on the lihe II of Fig. 2, of a furnace embodying my invention;

Fig. 2 1s a top plan view of the device shown in Fig. 1';

Fig. 3 is a view, ,in vertical section, taken on the line III-III of Fig. 4, of a modified form of furnace embodying my inven tion, and r Fig. 4 is a top plan view ofthe furnace shown-in Fig. 3;.

. Referring more made either of meta'l'or of a suitable elec-' trio-insulating material, as may be found" rests upon two spaced locks 16 of asuitmay be provided particularly to 1 and 2 of the drawings, I; have there shown an} induction *furnace of}. the surrounded-pool 1 type, as embodyin an :outer open-top casing 11 which may e substantiallyrectangular in formbut inay' also be of some other" shape, if desired. Theflcasing 11 .may be able refractory electric-insulating material, and the blocks 16 rest upon a similar plate 17. Short bolts or screws 18 and 19 may be provided to holdthe crucible on the blocks and the blocks on the plate, but these details are shown for illustrative purposes only and constitute no particular part of my invention.

Two sets of coils 21 and 22 are provided, each including a plurality of turns, the turns of the respective coil parts or sections bein substantially identical, andithe longitudina ,axes of the two parts of the energizing coils being symmetrically, oppositely, and angularly inclined, relative to the longitudinal axis of the crucible, in substantially the manner shown in Fig. 1 of the drawings.

Electrical connections (not shown) are 2 provided between the ends of the two coils to connect them in either electrical series relation or in parallel-circuit relation, as may be desired,so that the fluxes generated by the coils shall be added to each other. Electric insulatin tween the adjacent individual turns of each coil, in a manner well known in the art, to securely hold the coil parts in the positions shown in the drawin s'. we r 51 laminated structure located between the "sides of the crucible 12 and the side walls of the" casing 11 ma comprise a plurality material (not shown) of sheet-steel laminations 23 which are either or which' are built. up of abutting oroverlapping strips of magnetic material, in a manner well known in the art.. Blocks 24 may; be, provided in'the bottom of the cas ing- .11 and blocks126 may be provided at the top of the laminated structure, both sets of blocks being of electric-insulating material, in order to holdthe laminated struc ture in its proper operative position within the casing. Clamping screws 27, extending through a top wall of the casing, may be provided to hold the laminations tightly in their proper operative positions.

. Referring more particularly to Figs. 3 and 4 of the drawings, 1 have there illustrated a casing 3.1 substantially the same as casing 11, and a crucible 32 has substantially the same form as crucible 12 and is supported in substantially the same manner. Two coil parts 33 and 34 are provided, each part being substantially the same as the coil parts 21 and 22. g

A laminated structure 36 is provided, which is somewhat different from the laminated structure 23 of Figs. 1 and 2, the individual elements thereof being of substantially U-shape and laminated in a direction coinciding with the longitudinal axis of the crucible 32.

Means for supporting the crucible 32 comprise a plate 37 of electric-insulating material, a superposed plate 38 between which extends the intermediate portions of the laminated members36, and blocks 39 of I electric-insulating material, held by screws or by any other suitable means. The individual turns of the parts 33 and 34 of the energizing coil may be spaced from each other by suitable electric insulating material (not shown) and from the side walls of the crucible by a plurality of strips 41.

It may be noted that the coil provided for effecting a transfer of electric energy into material 42, shown in the respective crucibles in the form of molten metal, has a part of each turn of each coil portion locatednot only at one side of, but also below, the crucible. That part of each turn located laterally of thecrucible is adjacent to the top portion thereof, and it may also be noted that the shape of each turn is substantially rectangular. The top of the crucible is left open or uncovered and, with the 'ositions of the coil parts, as shown,extenj ing'laterally from that diameter of the crucible which extends through the pouring s out 13, this'pouring spout will be free and c ear.

The device embodying my invention thus provides a relatively simple and highly eflicient coil structure, each turn of each coil part being the same as the other turns and each turn being located adjacentv to two sides of the crucible, whereby a better transfer of electric energy into the material to be heated is effected. I have shown the usual trunnions on the casings for suitably mounting the furnace to permit of tilting it to pour the molten metal.

Since various modifications may be made in the device embodyin my invention without departing from t e spirit and scope thereof, I desire that only such limitations shall be placed thereon as are imposed by the prior art or are set forth in the appended claims.

'I claim as my invention:

1. In an electric induction furnace, in combination, a crucible and a two-part energizi ng coil for said crucible, the longitudinal axes of the two parts of the coil being symmetrically and oppositely inclined angularly with respect to the longitudinal axis of the crucible and intersecting the same above the bottom of the crucible.

2. In an electric induction furnace, in combination, an open-top crucible and an energizing coil therefor, the bottom portion of a turn of the coil being located below the crucible and the top portion of a turn being located laterallyof the crucible.

3. In an, electric induction-furnace, in combination, an opentop crucible and an energizing coil for said crucible having a plurality of coplanar turns of the same shape and dimensions, the lower portion of a turn of the coil being located below the crucible and the top ortion of a turn being located laterally of t e crucible.

4. In an electric induction furnace, in combination, an open-top pot-type crucible and a two-part energizing coil for said crucible, each vpart having a plurality of coplanar turns of substantially rectangular shape and of the same size, the axes of the coils being symmetrically and oppositel inclined angularly relative to the axis 0 the crucible.

5. In an electric induction furnace, the combination with a crucible having a pouring spout, the axis of the crucible being normally vertical, and a two-part energizing coil for said crucible, the lower portions of the turns of the respective parts of the coil being located closer together than the upper parts thereof and the pouring spout of the crucible being located at its upper end and between the s aced' upper portions of the two arts of t e coil.

6. 11 an electric induction furnace, the combination with a vertical-axis crucible having apouring spout, and a two-part energizing coil for said crucible, each part having a plurality of turns and the axes of the turns of each part being oppositely inclined angularly relative to the axis of the crucible, the spout extending laterally of thel crucible between the spaced parts of the 001 7. Inan electric induction furnace, in combination, a crucible, an energizing coil each turn of which is located adjacent to two difl'erent faces of the crucible, and laminated material outside of said coil to provide an incom lete magnetic circuit for flux gene rated y said coil.

In testimony whereof, I have hereunto subscribed my name this 30th day of July,

CLIFTON S. WILLIAMS.

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